Voters cast ballots Tuesday as the competition for the Democratic presidential nomination expanded significantly with contests in 14 U.S. states.

About one-third of the delegates that will be awarded during the state-by-state voting process are up for grabs Tuesday, including the biggest pot of candidates at stake in the western state of California.

After one-off contests in Iowa, New Hampshire, Nevada and South Carolina, the so-called Super Tuesday event brings a national tone to the nomination process, with voters in western, southern, northeastern and midwestern states all taking part on the same day, along with those in the U.S. territory of American Samoa.

Sitting in third place in the delegate count is Massachusetts Senator Elizabeth Warren, who earned all eight of hers a month ago in Iowa before a series of disappointing finishes. She is in a tight race in Massachusetts with Sanders, according to recent polls.

Minnesota Senator Amy Klobuchar announced the end of her candidacy on Monday, and gave her endorsement to Biden at an evening rally. She was one of a group of moderate Democrats to voice last minute support for Biden.

Besides expanding to a larger number of states, Tuesday's voting comes at a time of change in the race.

Minnesota Senator Amy Klobuchar announced the end of her candidacy on Monday, and gave her endorsement to Biden at an evening rally. She was one of a group of moderate Democrats to voice last minute support for Biden.

Also endorsing Biden on Monday was former South Bend, Indiana, Mayor Pete Buttigieg, who ended his own bid for president on Sunday after ascending from little-known status to winning the Iowa caucuses and coming in second to Sanders in New Hampshire.

Billionaire Tom Steyer also ended his campaign after finishing in third place, with no delegates, in South Carolina where he had hoped his strongest polling could yield positive results.

Super Tuesday Voters 2020

Competition for Democratic presidential nomination expands significantly with contests in 14 US states

Bloomberg

In an addition to the race, former New York City Mayor Michael Bloomberg is appearing on ballots for the first time. He joined the race months after his competition and decided to skip contesting the four February states in order to focus his early campaign on Super Tuesday. The billionaire spent $400 million on a massive ad campaign targeting Super Tuesday states.

Hawaii Congresswoman Tulsi Gabbard is also on the ballots Tuesday, but she has struggled to gain support as she finished no better than seventh in any of the February contests and last qualified to participate in a debate in November.